Electrode structure for electric discharge devices



Fig.2.

RLJ. BONDLEY DISCHARGE DEVICES Filed Dec. 9, 1944 lnvehtcn-z Ralph J. Bondle g,

'EH.IE('.-TROIJE STRUCTURE FOR ELECTRIC I I 1 1 z I I I I 1 I I I I I I 1 I I 1 I I 1 I 1 I 1 1 z I 1,

Jan. 25, 1949.

His Attornes.

Patented Jan. 25, 1949 ELECTRODE STRUCTURE FOR ELECTRIC DISCHARGE DEVICES Ralph J. Bondley, Scotia, N. Y., assignor to Gen gal Electric Company, a corporation of New ork Application December 9, 1944, Serial No. 567,367

8 Claims. (Cl. 250-275) presented by the change in electrode spacing resulting from changes in temperature. In accordance with the teachings of the present invention, an improved grid structure is provided which remains planar with considerable changes in operating temperature. i The individual conductors of the grid structure also remain substantially stationary within the plane of the grid with variations in temperature so that the grid wires of a multi-grid tube may be maintained in aline ment.

It is an object of my invention to provide a new and improved electrode structure.

It is another object of my invention to provide a new and improved control grid including a plurality of individual grid wires which retains its shape and position during variations in operating temperature. I

In accordance with an illustrated embodiment of my invention, an apertured disk provides a support for a plurality of grid wires. Each of the grid wires is substantially U-shaped with the base of the U being elongated and straightened to span a major portion of the aperture. Each of the wires or conductors is attached to the support by the arms of the U which extend at right angles to the base portion. The total grid structure includes two sets of these U-shaped members arranged in nested and opposed relation. With this arrangement, the straight portions of the individual grid conductors remain'parallel andin the initial plane with a wide range of temperature variations, all of the expansion being taken up in movement of the arm portions of the U-shaped conductors. In a second modification, the grid conductors are essentially V- shaped and are arranged in four sets of nested conductors each lying within one quadrant of the aperture of the grid support, while in a third.

elevational view of a section of a high frequency electric'discharge device including a grid constructed in accordance with my invention; Fig. 2 is a plan view of the grid structure shown in Fig. 1; Fig. 3 is a plan view of a modification, and Fig. 4 is a plan view of a still further modification.

Referring now to the drawing, I have shown my invention embodied in a high frequency electric discharge device formed of a series of three similar metal disks I, 2 and 3 which are insulatingly separated by glass cylinders 4 and 5 sealed between them. The disks provide a portion of the enclosing envelope and in addition provide the high frequency anode, grid and cathode terminals, respectively, of the discharge device. The upper disk I supports a cylindrical anode structure 6 which terminates externally in a threaded portion I adapted for connection to a current supply terminal. The anode has a central bore 8 which connects with the main discharge space through openings 9 and through which evacuation of the discharge envelope may be carried out. After evacuation, the envelope is sealed by means of a body of. glass 10 fused to the extremity of a metal tubulation l I which is brazed into the anode bore 8. The cathode of the device is provided by a disk-like cathode member [2 which may be coated on itsupper surface with electron emissive material such as an alkaline earth oxide. The cathode is supported from the lower disk 3 by a supporting cylinder l3 and a length of relatively thin metal foil M which may to advantage be a sleeve of fernico metal for minimizin the transfer of heat from the cathode to the cathode support. The cathode surface is adapted to be raised to operating temperature by a flat helical heater l5 supported adjacent the lower side of the cathode I2 by rigid conductors l6 and I? which extend through the disk 3 and are sealed to a tubulation It! by a body of glass IS. A me.- tallic heat shield 20 lying adjacent the lower side of the heater element may be provided and, as illustrated, is supported from one of the lead-in conductors i! by an arm 2| which is formed by punching out a portion of the disk 20. The cathand caramel: and suppbrts a'plurality of' r'id conductors. As best illustrated in Fig. 2, each of the conductors is substantially U-shaped having the base elongated and straightened so that a plurality of parallel conductors 22 extend across the aperture formed in the grid supporting disk 2. Each of the conductors is supported from the disk 2 by thearm portions Zdthereof which extend at substantially right angles to the parallel portions 22. The ends may be secured to the grid disk in any suitable manner and in the il lustrated embodiment are received in slots formed around the periphery of the apertured grid disk. As illustrated in 2, the U-shaped conductors are arranged in two opposed nested groups and, as illustrated in Fig. l, the. conductors are of substantially greater cross section in a direction perpendicular to the plane of the grid. With the construction just described, practically all move ment of the grid conductors due to variationsin temperature of the grid structure is taken up in the arm portions 23 so that the straight conductors remain stationary both in .the plane of the grid and ina direction perpendicular to, the plane of the grid. This has an important ,advantage in tubes where the electrode spacings are small and in multi-grid tubes where it is desired to keep alinement between corresponding conductors of the different grids.

In Fig. 3 is illustrated a modification of my invention in which the individual grid conductors 24 are substantially V-shapcd. As clearly indicated in Fig. 3, the conductors are arranged in four opposed nested groups with the apexes of the conductors of each group lying on a radius of the grid aperture. While the grid structure of Fig. 3 is very satisfactory from the standpoint of maintaining its planar shape and, therefore, maintaining fixed spacings between the various electrodes, there is lateral movement of the conductors in the plane of the grid and from this point of view this structure is not as desirable as the modification of Fig. 2, particularly in tubes employing a plurality of grids.

In Fig. 4 I have illustrated an embodiment of my invention which is in general similar to the modification of Figs.,1 and 2, but which offers some advantage from the standpoint of rigidity in a direction perpendicular to the plane of the grid. The individual conductors are substantially L-shaped having relatively long linear parts 25 secured at one end directly to disk 2 and secured at the other end to the disk 2 by arms 26 which extend at right angles to the linear parts 25 and form the bases of the L-shaped conductors. It is believed clear that expansion and contraction of the. linear parts 25 will be taken care of by movement of the arms 26 and that the parts 25 will remain substantially stationary.

While I have shown and described a particular embodiment of my invention, it willbe obvious to those skilled in the art that changes and modifications may be made Without departing from my invention in its broader aspectsfland I, .therefore, aim in the appended claims -.to cover. all such changes and modifications as fall within the true spirit and scopeof my invention.

What I claim as new and desire .to satiety Letters Patent of the United States is:

1. An electrode structure for an electric discharge device comprising a supporting member having an aperture therethrough, a plurality of conductors secured to said supporting member at their ends and overlying the aperture, each of said conductors having an intermediate U-shaped portion including an elongated linear central part 4 and arms extending from the ends of said linear part at an angle thereto, said U-shaped portions being of varying sizes and said conductors being attached to said support with the conductors in a. plurality of nested groups with the linear parts substantially parallel and the U-shaped portions of all said conductors substantially coplanar.

2. An electrode structure for an electric discharge device comprising a plate-like supporting member having a circular aperture therethrough, a. plurality ofv conductors secured to said supporting member at their ends and overlying the aperture, each of said conductors having an intermediate U-shaped portion including an elongated linear central part and arms extending from the ends of said linear part and at an angle the reto,.said U-shaped portions being of varying sizes and said conductors being attached to said support with the conductors in two nested groups With the linear parts substantially parallel to a diameter and with the U-shaped portions of the conductors of the two groups facing oppositely with respect to-said diameter.

3-.-Anelectrode structure for an electric discharge device comprising a plate-like supporting member having an aperture therethrough, a plurality of conductors secured to said supporting member at their ends and overlying the aperture, each of said conductors having an intermediate U-shaped portion .including an elongated linear central part and arms extending from the ends of said linear part and at an angle thereto,- said U-shaped portions being of varying sizes and said conductors being attached to said support with the conductors in two nested groups with the linear parts substantially parallel and with the arms of the conductors of one group extending oppositely with respect to the arms of the other group.

4;..An electrode structure for an electric discharge device comprising a supporting member having an aperture therethrough, a plurality of conductors secured to said supportin member at their ends and overlying the aperture, each of said conductors having an intermediate V-shaped portion including elongated linear parts extending at an angle to each other, said V-shaped-portions being-of varying sizes and said conductors being attached to said support with the conductor in a plurality of nested-groups with the V- shapedportions of all said conductors substantially coplanar.

5. An electrode structure for an electric discharge device comprising a supporting member having a circular aperture therethrough, a plurality of conductors secured to said supporting member at their ends and overlying the aperture, each of-said conductors having an intermediate V-shaped portion including elongated linear parts extending at an angle to each other, said V-shaped portions being-of varying sizesand said conductors being. attachedto said support with the conductors in a plurality-of nested groupswith the apexes of all the conductorsof eachgroup. lying on a radius of said aperture.

6.. An electrode structure for an electric discharge device comprisi a supporting member having an aperture'therethrough. a plurality of Iconductors' -secured to said'supporting member and overlying the aperture, each of said conductors including an elongated linear part and an arm extending from the end of said linear part at an angle thereto, said conductors being of varying lengths and being attached to said supporting member at theirrespective-extremities with the conductors in a plurality of nested groups with the said linear parts substantially parallel to one another and substantially coplanar.

7. An electrode structure for an electric charge device comprising a plate-like supporti:..; member having a circular aperture therethrougl'i, a plurality of conductors secured to said supporting member and overlying the aperture, each of said conductors having an elongated linear part and an arm extending from one end of said linear part and at an angle thereto, said conductors being of varying lengths and attached to said support with the conductors in two nested groups and with the linear parts substantially parallel to a common diameter and with the arm portions of the conductors of the two groups extending oppositely with respect to said diameter.

8. An electrode structure for an electric discharge device comprising a supporting member having an aperture therethrough, a plurality of conductors secured to said supporting member at their ends and overlying the aperture, each of said conductors having an intermediate L-shaped portion including elongated linear parts extending at an angle to each other, said L-shaped portions being of varying sizes and said conductors being attached to said support with the conductors in a plurality of nested groups with the i..- portions of all said conductors substantially coplanar.

RALPH J. BONDLEY.

REFERENCES CETED he following references are of record in the 55% this patent:

UNITED STATES PATENIS 

